The Environmental Protection Agency has denied the most recent petition from environmental groups that asked the agency to reconsider a 2012 decision not to immediately pursue an endangerment finding for leaded avgas.

State and local aviation officials recently learned about the latest efforts to transition from 100LL avgas to an unleaded fuel and got an update on the initiative to reform third class medical certification.

The FAA has selected four unleaded aviation fuels to undergo initial testing at the agency's William J. Hughes Technical Center. Two fuels developed by Swift Fuels and one fuel each developed by Shell and TOTAL will undergo laboratory and rig testing beginning this fall and concluding in fall 2015.